Priming charge for mines.



L. AHT'IO'. PRIMING GHABGE FOB MINES. APPLICATION FILE?) JUNE 15 1908.

938,553. Patented Nov. 2, 1909.

Q/alwgssaS f LOUIS canto, or nnumanx'r, GERMANY.

rnmrne cannon ron MINES.

Specification of Letters Yatent.

Application filed June 15, 1908. Serial No. 438,578.

To all whom it may concern:

Be it known that I, LoUIs- Carine, mam faeture-r, a citizen of the French Republic, residing at Ingolstitdterstrasse', Neumarkt, Upper Palatinate, Germany, have invented new and useful Improvements in Priming forms a layer 01 of small height in such tions bared of insulation and Charges for Mines, of which the following isa specification.

The subject of my invention is an imroved priming charge to be electrically red in mines. y

The essential feature of my invention is that firing is done with the aid of an intermediate priming-powder containing aluminum, placed between the conducting-wires. The aluminum is used in a finely divided state, for instance in. the form of aluminumdust, aluminum-wool, etc. If desired, the aluminum can be partly replaced by another metal in'finely comminuted-form, such as copper-, tin-,' or magnesium-dust or the like, or an aluminum alloy in a state of fine division may be employed.

In the accompanying drawing a fuse provided with the new arrangement is represented in longitudinal section.

a is a socket formed of cardboard, metal or the like said socket being formedwith a circular projection-a b is an insulating material (sulfur, sealing-wax or the like) into which the electric wires 0 are to be embedded. .Said material I), which is intended to afford the necessary insulation of the wires c, ismaintained in place by the part a of the socket a; 0 are the insulated wires which are twlsted together, 'the upper extremities of said wires extending somewhat through the u per surface of the insulating material I) an having their relativel adjacent porbeing surrounded by the comminuted aluminum which manner that the incandescing mixture (1 lies between the bared portions ofthe wires; e is the igniting mass composed of black pow der, gun-cotton (pyroxylin), fulminate of mercury or the like; 7 is an obturator consisting of wax, orthe like. The upper part of the fuse above the obturator f rece ves the cartridge or the like.'

The priming-charge of aluminum, or of a mixture of aluminum and other metals, can

if necessary also be mingled 'with substances containing oxygen and (or) carbon, which in consequence of the elevation of the reac-. titan-temperature contribute to theignition 4 of the detonating-composition, or of the explosive direct.

I am aware that mines and the like-have already been fired electrically insuch a manner that the detonating-composition, or the Patented Nov. 1909.

explosive itself, has been ignitedby means of an intermediate primingspowder, brought to combustion or explosion by means of the electric current. It is, however, novel to the art to employ for this purpose aluminum powder, aluminum mixed with other metals, or an aluminum alloy.

I am also aware that the ignition has been effected by means of a so-called incandescent bridge or wire. The employment of powdered aluminum, according to my invention, however, is much more advantageous. For metallic powders, as is well known, are bad conductors, so that the aluminum powder, offering a highelectric resistance, is immediately heated and thus causes numerous small luminous arcs to form between the individual particles, whereby the ignition is much better-transmitted than, for instance,

is the case when an incandescent wire is employed. Similar effects are attained when the aluminum is partly replaced by another metal. l

The employment of aluminum as an intermediate priming-powder has the further advantage that after firing the mine or the the electric current is also conducting. T iis is of'importance, especially in the case of mines andthe like connected in series, for should like, the cinder which has been formed by the influence of the heat developed b one or more. mines have missed fire, a subsequent current enerated by the induction apparatus can sti 1 be sent through the primers connected in series andso fire these unexploded mines. 1

The following further advantages of the use of aluminum are of importance. 1: By using comminuted aluminum as a primary igniter the temperature of ignition is relatively low, but the temperature of ex losiqn -'s very much raised, so that the sa ety of ignition is increased accordingly. 2: Because aluminum, asvery well known, is only oxidizable with great difficulty, the stability of the priming-powder 1s increased. 3: The

action of the fuse even with weak currents is very perfect and very reliable, as, for instance, a magnetoelectric igniting machine working with a tension of 506 volt with 0.10 ampere is sufiicient for igniting 20 fuses tween the two electrodesor wire-ends, my

. in oneopera'tion. 4; In order'to fill 100,000 .fuses, only 1 kilogram of aluminum is ne cessary, so that the use of aluminum as a primaryi iter or primary powder is very economics, and ,cheap. As, moreover, avery Small quantity of aluminum powder. and the like is suflicientto make a good contact benew method also possesses the advantage of economy over prior intermediate primingpowders, whose composition is often of a complicated nature, and over incandescent 1 wires, which are made of platinum and are thus ve expenslve.

Ifit s "desired to add to the aluminum powder an oxygen-carrier, such as potassiumor sodium-nitrate, or the like, this can be done up to about 50% of thequantity.

If the aluminum is to be used min led withanother metal, theremay .be adde to 'it, for instance, one third-of the latter in -'comminuted condition. By thus substitut- T mg another metal for a portion of the alumlnum, the following advantages are attained. Firstly, if. the metal added is cheaper than aluminum, the/price of the final product, that is, the priming-powder,

is fower'. "Secondly, by the addition of the other metal the possibility is presented of regulating the firing-temperature, or keeping it exactly within the most favorable limits, for, 'as is well known, the temperatures at which the various metals become mcan'descent under the influence of heat,

that is under thwaction of the electric current,difl er greatly from each other.

aturally, instead of a single metal, a mixture of aluminum; 4

v The aluminum owder, or mixture containing comminute aluminum and the like,

, or the aluminum alloy in comminuted form v may with advantage be used as intermediate priming-powder-in the manufacture of fuses .in a state of fine division several such can be added to the for mines, as it is sufiicient to strew the powdered material between the wire ends or electrodes of spark-fuses or incandescentgapI-fuses or the like.

aving thus described my invention, what Iclaim as new and desire to secure by Letters Patent is z- 1. In an electric fuse the combination of insulated conducting wires having relatively adjacent portions bared of insulation, an incandescing conductor comprising a mixture of finely divided aluminum, another metal in a state of fine division, an oxygen carrier 1 and a carbon carrier, said mixture lying be tween the bared portions of the wires.

2. In an electric fuse the combination of insulated conducting wires having relatively adjacent portions bared of insulation, an incandescing conductor comprising a mixture of finely divided aluminum, another metal in a state of fine division, and an oxygen carrier, said mixture lying between the bared portions of the wires. Y t

3. In an electric fuse the combination of insulated conducting wires having relatively adjacentportions bared of insulation, an incandescingconductor comprising a mixture of finely divided aluminum and another" metal in a state'of fine division,'said mix-- 

